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United States Patent |
5,339,741
|
Craven
,   et al.
|
August 23, 1994
|
Precision fireworks display system having a decreased environmental
impact
Abstract
A system and method for launching projectiles, such as fireworks
projectiles, which explode in the air into a pyrotechnic display. The
projectile includes a shell constructed from a binding agent and an
explosive additive which explodes the shell into small particles. The
explosive additive, which may be nitrocellulose, causes the exploded
particles to be rapidly burned and consumed to form lightweight, inert
flakes that fall harmlessly to the ground. The projectile is aimed and
launched by a launcher using a compressed gas to rapidly expel the
projectile from a launching tube. Once in the air at a predetermined
location in the sky, an electronic fuse inside the projectile operates to
detonate the projectile into its intended pyrotechnic display. The fuse is
extremely accurate and enables detonation of the projectile at precise
altitudes. An electronic control system controls launching and detonation
of the projectiles in a precise and repeatable manner.
Inventors:
|
Craven; B. Thomas (Windermere, FL);
Wiedefeld; William G. (Clermont, FL);
Poor; Kyle W. (Clermont, FL);
Johnson; Bruce S. (North Hollywood, CA);
Sogge; John W. (Orlando, FL);
Peterson; Michael H. (Glendale, CA);
Adamson; William G. (Pacoima, CA);
Froelich; Ronald W. (Covina, CA)
|
Assignee:
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The Walt Disney Company (Burbank, CA)
|
Appl. No.:
|
817591 |
Filed:
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January 7, 1992 |
Current U.S. Class: |
102/361; 102/206; 102/431; 102/493 |
Intern'l Class: |
F42B 004/04 |
Field of Search: |
102/328-330,361,206,431,493
|
References Cited
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|
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|
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| |
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| |
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| |
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| |
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| |
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| |
Other References
Drawing re "Oriental Shell `Warimono` Class* Single-Break" giving detailed
description thereof, one page.
Drawing describing in depth "Canister Shell Repeating Color/Effect" one
page.
Drawing describing in depth"`Roman` Candle"; `Gerbe` (Fountain); and `Mine
Bag`, one page.
Cover page of Scientific American magazine No. C.2, one page showing
Fireworks, Article entitled "Pyrotechnics" by John A. Conkling, Scientific
American magazine Jul. 1990, pp. 96-102.
|
Primary Examiner: Nelson; Peter A.
Attorney, Agent or Firm: Pretty, Schroeder, Brueggemann & Clark
Claims
We claim:
1. A system for creating a fireworks display, comprising:
(a) a fireworks projectile designed to explode into a fireworks display in
the air, the fireworks projectile comprising a shell containing an
explosive charge, wherein the shell is constructed from a composition that
includes an additive such that upon detonation of the charge the shell is
exploded along with the charge into small particles that are rapidly
burned and consumed;
(b) an electronic fuse connected to the explosive charge in the fireworks
projectile for detonating the explosive charge and exploding the fireworks
projectile into the fireworks display in the air at a predetermined time
period after launch; and
(c) a launcher for launching the fireworks projectile into the air, in
which a non-explosive launching medium comprising a compressed gas at a
controlled pressure is used to propel the fireworks projectile from the
launcher into the air.
2. The system of claim 1, wherein the additive is nitrocellulose and the
shell has a configuration which facilitates exploding of the shell into
small particles upon ignition.
3. The system of claim 2, wherein the configuration comprises a plurality
of grooves formed on the inner surface of the shell.
4. The system of claim 2, wherein the configuration comprises a plurality
of ridges formed on the inner surface of the shell.
5. A system for creating a fireworks display, comprising:
(a) a fireworks projectile designed to explode into a fireworks display in
the air;
(b) a launcher for launching the fireworks projectile into the air, in
which a compressed gas is used to rapidly expel the fireworks projectile
from the launcher into the air; and
(c) an electronic fuse connected to the fireworks projectile for exploding
the fireworks projectile in the air at a predetermined time period after
launch, wherein the electronic fuse comprises:
energy storage means for receiving electrical energy and storing it,
counting means for initiating and incrementing a count at a predetermined
frequency, wherein the counting means includes a precounter sequence after
launch and a main counter sequence which commences upon expiration of the
precounter sequence, and
count storage means for storing a predetermined value that indicates a
desired time delay.
6. A system for creating a fireworks display, comprising:
(a) a fireworks projectile designed to explode into a fireworks display in
the air;
(b) an electronic fuse connected to the fireworks projectile for exploding
the fireworks projectile in the air at a predetermined time period after
launch; and
(c) a launcher for launching the fireworks projectile into the air, in
which a non-explosive launching medium comprising a compressed gas is used
to rapidly expel the fireworks projectile from the launcher into the air.
7. The system of claim 6, wherein the fireworks projectile comprises:
(a) an explosive charge connected to the electronic fuse, wherein the
charge contains a composition adapted to explode into the fireworks
display upon ignition by the fuse; and
(b) a shell containing the explosive charge, wherein the shell is
constructed from a composition including a binding agent and an additive,
such that upon ignition the shell is exploded along with the charge into
small particles that are rapidly burned and consumed and which fall to the
ground as lightweight inert particles.
8. The system of claim 7, wherein the binding agent is paper or plastic
material and the additive is nitrocellulose.
9. The system of claim 8, wherein the shell contains a range of between
approximately 0.6 gm/cm.sup.3 to approximately 1.3 gm/cm.sup.3
nitrocellulose.
10. The system of claim 8, wherein the nitrocellulose is initially mixed
with the binding agent and thereafter formed into the shell.
11. The system of claim 8, wherein the binding agent is formed into the
shell and the nitrocellulose is subsequently applied to a surface of the
shell.
12. The system of claim 7, wherein the shell has a configuration adapted to
facilitate exploding of the shell into small particles upon ignition.
13. The system of claim 12, wherein the inner surface of the shell is
scored with a plurality of grooves to facilitate exploding of the shell.
14. The system of claim 13, wherein the plurality of grooves are arranged
to intersect each other and divide the shell into small regions.
15. The system of claim 13, wherein the grooves comprise a plurality of
horizontal grooves which intersect a plurality of vertical grooves.
16. The system of claim 13, wherein the grooves extend into the inner
surface of the shell by a distance equal to approximately one-half of the
thickness of the shell.
17. The system of claim 12, wherein the inner surface of the shell is
scored with a plurality of ridges to facilitate exploding of the shell.
18. The system of claim 17, wherein the plurality of ridges are arranged to
intersect each other and divide the shell into small regions.
19. The system of claim 17, wherein the ridges comprise a plurality of
horizontal ridges which intersect a plurality of vertical ridges.
20. The system of claim 17, wherein the ridges extend radially from the
inner surface of the shell by a distance equal to approximately one-half
of the thickness of the shell.
21. The system of claim 6, wherein the launcher comprises:
(a) a pressure vessel containing the compressed gas;
(b) a launching tube having a lower end connected to the pressure vessel
and an open end for expelling the fireworks projectile;
(c) a valve connected between the pressure vessel and the launching tube;
and
(d) a control apparatus for opening and closing the valve to accurately
control the introduction of pressure from the pressure vessel to the
launching tube to expel the fireworks projectile from the open end of the
launching tube.
22. The system of claim 21, wherein the compressed gas is introduced into
the launching tube at pressures between approximately 20 to 150 psi.
23. The system of claim 21, further comprising a breech between the
pressure vessel and the launching tube for loading the fireworks
projectile in the launcher.
24. The system of claim 23, wherein the breech comprises:
(a) an opening in the lower end of the launching tube through which the
fireworks projectile is loaded;
(b) a stop mechanism for maintaining the fireworks projectile at a fixed
position within the launching tube; and
(c) a cover on the launching tube adapted to move between an open position
to permit loading of the fireworks projectile and a closed position to
permit launching of the fireworks projectile after loading.
25. The system of claim 24, wherein the cover on the breech comprises a
sleeve surrounding the launching tube, the sleeve being axially slidable
with respect to the launching tube between the open position, in which the
sleeve is axially spaced from the opening, and the closed position, in
which the sleeve covers the opening.
26. The system of claim 24, wherein the cover on the breech comprises a
door pivotally connected to the breech such that, in the open position,
the door pivots outwardly away from the opening and, in the closed
position, the door pivots inwardly to cover the opening.
27. The system of claim 23, wherein the launching tube is pivotally
connected to the breech, and wherein the breech comprises an enclosure
having a cylinder for receiving the fireworks projectile, such that the
launching tube can be moved into and out of registration with the cylinder
for launching and loading of the fireworks projectile, respectively.
28. The system of claim 23, wherein the breech comprises a plurality of
fireworks projectile holding tubes that are indexed into and out of
registration with the launching tube to permit successive launching of a
plurality of fireworks projectiles.
29. The system of claim 28, wherein the plurality of fireworks projectile
holding tubes are arranged in a straight row.
30. The system of claim 28, wherein the plurality of fireworks projectile
holding tubes are arranged in a circular or cylindrical manner.
31. The system of claim 6, further comprising an aiming apparatus for
adjusting the position of the launcher and aiming of the fireworks
projectile.
32. The system of claim 31, wherein the aiming apparatus comprises a
plurality of legs which support the launcher and which are adjustable to
change the angle of the launcher with respect to the ground.
33. The system of claim 6, wherein the electronic fuse comprises:
energy storage means for receiving electrical energy and storing it;
counting means for initiating and incrementing a count at a predetermined
frequency; and
count storage means for storing a predetermined value that indicates a
desired time delay.
34. The system of claim 33, wherein the energy storage means comprises a
plurality of storage capacitors.
35. The system of claim 33, wherein the counting means includes a local
oscillator that generates a series of pulses.
36. The system of claim 35, wherein the count storage means comprises a
binary counter that receives the pulses from the local oscillator and
increments its count with each pulse.
37. The system of claim 33, wherein the counting means includes a
precounter sequence after launch and a main counter sequence which
commences upon expiration of the precounter sequence.
38. The system of claim 37, wherein the main counter sequence will cause
detonation of the fireworks projectile when the main counter sequence
elapses, and wherein the main counter sequence will not be initiated until
an actual launch has occurred, as determined by the precounter sequence
which elapses only after an actual launch has occurred.
39. A system for creating a fireworks display, comprising:
(a) a fireworks projectile designed to explode into a fireworks display in
the air;
(b) an electronic fuse connected to the fireworks projectile for exploding
the fireworks projectile in the air at a predetermined time period after
launch; and
(c) a launcher for launching the fireworks projectile into the air, wherein
the launcher comprises:
a pressure vessel containing a compressed gas,
a launching tube having a lower end connected to the pressure vessel and an
open end for expelling the fireworks projectile,
a valve connected between the pressure vessel and the launching tube, and
a control apparatus for opening and closing the valve to accurately control
the introduction of pressure from the pressure vessel to the launching
tube to expel the fireworks projectile from the open end of the launching
tube.
40. The system of claim 39, wherein the control apparatus comprises a
central controller that produces control signals for initiating a launch
sequence, and a local control unit that receives the control signals from
the central controller, produces a predetermined ignition delay time, and
controls the opening and closing of the valve, and wherein the electronic
fuse receives the ignition delay time from the local control unit and
ignites the fireworks projectile after the delay time has elapsed
following launch of the fireworks projectile.
41. A system for creating a fireworks display, comprising:
(a) a fireworks projectile that is designed to explode into a fireworks
display in the air, the fireworks projectile comprising a shell containing
an explosive charge, wherein the shell is constructed from a composition
that includes an additive such that upon detonation of the charge the
shell is exploded along with the charge into small particles that are
rapidly burned and consumed;
(b) an electronic fuse connected to the explosive charge in the fireworks
projectile for detonating the explosive charge and exploding the fireworks
projectile into the fireworks display in the air at a predetermined time
period after launch; and
(c) a launcher for launching the fireworks projectile into the air, wherein
the launcher comprises:
a pressure vessel containing a compressed gas,
a launching tube having a lower end connected to the pressure vessel and an
open end for expelling the fireworks projectile,
a valve connected between the pressure vessel and the launching tube, and
a control apparatus for opening and closing the valve to accurately control
the introduction of pressure from the pressure vessel to the launching
tube to expel the fireworks projectile from the open end of the launching
tube.
42. The system of claim 6, further comprising an electronic controller for
communicating with and programming the launcher to launch the fireworks
projectile and for communicating with and programming the electronic fuse
to explode the fireworks projectile in the air at a predetermined time
after launch.
43. The system of claim 42, wherein the electronic controller comprises a
central controller that produces control signals for initiating a launch
sequence, and a local control unit that receives the control signals from
the central controller, produces a predetermined ignition delay time, and
controls the launcher, wherein the electronic fuse receives the ignition
delay time from the local control unit and ignites the fireworks
projectile after the delay time has elapsed following launch of the
fireworks projectile.
44. The system of claim 6, wherein there are a plurality of fireworks
projectiles with electronic fuses and a plurality of launchers controlled
by an electronic controller for communicating with and programming each of
the launchers to launch each of the fireworks projectiles at a
predetermined time to a predetermined altitude and location in the air,
and for communicating with and programming the electronic fuse of each of
the fireworks projectiles to explode the fireworks projectile in the air
at a predetermined time after launch.
45. The system of claim 44, wherein the electronic controller programs each
of the launchers and each of the electronic fuses such that the fireworks
projectiles explode in the air in relatively precise synchronization with
music, dialogue or other sounds.
46. A system for creating a fireworks display, comprising:
(a) a fireworks projectile designed to explode into a fireworks display in
the air;
(b) a fuse connected to the fireworks projectile for exploding the
fireworks projectile in the air at a predetermined time period after
launch; and
(c) a launcher for launching the fireworks projectile into the air, wherein
the launcher comprises:
a pressure vessel containing a compressed gas,
a launching tube for holding the fireworks projectile prior to launch,
wherein the launching tube has one end connected to the pressure vessel
and an open end for expelling the fireworks projectile, and
a control apparatus for controlling the introduction of compressed gas from
the pressure vessel to the launching tube to expel the fireworks
projectile from the open end of the launching tube.
Description
BACKGROUND OF THE INVENTION
The present invention relates to fireworks displays and, more particularly,
to a new method and system of presenting precision fireworks displays with
a decreased environmental impact.
"Pyrotechnics" is the "science of fire." Pyrotechnic displays, commonly
referred to as fireworks or fireworks displays, have been created and
enjoyed for centuries by millions of people. Over the years, the systems
and methods for creating the displays have remained substantially
unchanged.
The fireworks systems of the prior art are comprised essentially of two
main components, namely a pyrotechnic projectile and a mortar for
directing the pyrotechnic projectile into the air. The pyrotechnic
projectile itself consists of two principal components, comprising an
initial burst and a main burst. Black powder is one of the oldest
pyrotechnic propulsion agents and it is typically used as the initial
burst and main burst component. The main burst also includes pellets of
color composition known as "stars." Igniting the stars during detonation
of the main burst provides the light and color of the fireworks display.
Common pyrotechnic projectiles comprise an inner shell and an outer shell.
To preserve the main burst until aerial ignition, the main burst is
enclosed within the inner shell, while the initial burst is enclosed
within the outer shell. The pyrotechnic projectile also has two fuses in
the form of an initial fuse and a main fuse. The main fuse extends from
the initial burst in the outer shell to the main burst in the inner shell.
The initial fuse extends from the initial burst to the exterior of the
outer shell. By igniting the initial fuse, the initial burst is exploded
and propels the pyrotechnic projectile from the mortar into the air.
Contemporaneously, the main fuse is lit because the end of the main fuse
protrudes into the initial burst. The main fuse then takes a specific time
to burn into and ignite the main burst.
The pyrotechnic projectile can take on various shapes. For cylindrical
shells, the main burst includes stars which are randomly packed. Upon
detonation of the main burst, the shell opens, and the stars are ignited
in an irregular visual pattern. For round shells, the main burst consists
of the stars arranged around a central core of black powder. When the main
burst of the round shell is ignited, the stars are distributed in a round,
symmetrical pattern. Sometimes the shell will contain a flash-and-sound
powder, instead of stars, to produce a flash of light and a loud noise.
Factors in raising the pyrotechnic projectile to a particular altitude are
aerodynamic drag, projectile stability and the size of the initial burst.
In this regard, pyrotechnic projectiles are usually hand manufactured, and
various materials have been used to form the pyrotechnic projectile's
outer shell, including paper and plastics. The manufacturing variations,
therefore, can cause uncertainties in the final shape of the pyrotechnic
projectile. Hence, such manufacturing variations can create an outer shell
that is non-uniform in shape, which causes undesirable drag and
instability in flight. As a result, the altitude to which the pyrotechnic
projectile is launched can never be determined with precision. In addition
to the structural variations in the pyrotechnic projectile outer shell
structure, the variations in the quality and composition of the black
powder charge used in the initial burst can propel otherwise identical
projectiles to various different heights. This is explained in more detail
below.
A further related factor regarding altitude is the main fuse technology,
which governs detonation timing of the main burst after ignition of the
initial burst. The main fuse, used to detonate the main burst of the
pyrotechnic projectile, typically is a delayed chemical fuse. Existing
chemical fuses are usually non-uniform in their construction and therefore
exhibit a wide variation in their burn rate from one pyrotechnic
projectile to the next. As a result, it has been found that a pyrotechnic
projectile set to detonate at approximately 600 feet in the air may
detonate anywhere from between 500 feet and 700 feet, roughly a 16 percent
deviation.
Variations in black powder composition, black powder quality, pyrotechnic
projectile structure and mortar structure all contribute to the inherent
lack of uniformity of projectile height and position at the time of shell
ignition. Amounts of black powder in the initial burst, length and
orientation of the initial and main fuses, and composition and thickness
of the shell casings are only within tolerances obtainable during
non-precision hand manufacturing. Because of the lack of precise
repeatability during pyrotechnic projectile manufacturing, large
variations between the pyrotechnic projectile's ignition time and flight
path from pyrotechnic projectile to pyrotechnic projectile are the norm.
Historically, fireworks displays have not been precise, repeatable or
accurate. However, although it is not possible to exactly duplicate any
one display, by using different types of stars and/or flash-and-sound
powder, and by arranging them in the shell in a particular way, various
types of fireworks displays can be created when a variety of such
pyrotechnic projectiles are ignited simultaneously or in series.
From the foregoing, it can be seen that the typical pyrotechnic projectile
is a self-contained unit having its means of propulsion (i.e., the initial
burst) and mechanism for timing projectile detonation (i.e., the initial
and main fuses) incorporated into its structure. As such, these propulsion
and timing mechanisms are fixed by the structural composition of the
pyrotechnic projectile, which is pre-set at the factory. Hence, it is not
possible to adjust those parameters once the manufacturing process for the
pyrotechnic projectile has been completed.
Accordingly, it further can be seen that the launch and detonation of
existing pyrotechnic projectiles is an inexact science and is subject to
severe limitations and drawbacks. To determine the pyrotechnic projectile
path and altitude achieved, the amount of black powder in the initial
burst is significant, since a greater amount of black powder generates a
larger gaseous expansion within the mortar behind the pyrotechnic
projectile and a resultant higher projection into the sky. The limitation
on the height of the projection is based on the minimum burn rate of the
black powder, inasmuch as the rate of pressure increase cannot exceed that
which the inner shell can withstand, i.e., structural integrity of the
inner shell of the pyrotechnic projectile must be maintained.
For any given size of shell there is a practical limit to the altitude that
can be reached using black powder as the initial burst component.
Increasing the altitude requires increasing the acceleration rate up the
length of the mortar, and therefore increasing the burn rate of the
initial burst. However, as the initial burst is formulated to burn faster,
it becomes less controllable; as the rate of pressure rise increases, the
initial burst is consumed quicker and begins to exhibit explosive
detonation characteristics. The result is an exponential pressure rise
that will destroy a pyrotechnic projectile in the mortar.
Increasing the force which the inner shell casing can withstand, for
example, by increasing the shell thickness, causes a change in the
pyrotechnic projectile's performance. This change in performance, which
can cause a change in the characteristics of a fireworks shell, is
disfavored because it usually diminishes and/or alters the visual display
quality. Consequently, the projection height of the pyrotechnic projectile
is limited by the durability of the shell. Historically, it was not
possible to project the pyrotechnic projectile beyond a certain height,
relative to its diameter. For example, a pyrotechnic projectile having a
nominal six inch shell casing typically can be launched to an altitude of
between about 200-600 feet, with 600 feet being the practical limit. A
pyrotechnic projectile having a smaller shell casing will go lower and one
with a larger casing will go higher, with 1,000 feet being about as high
as they will go.
As noted above, the pyrotechnic projectiles are directed into the air
through the mortars. The mortars are cylindrical in shape. To propel the
pyrotechnic projectile from the mortar, the pyrotechnic projectile is
placed in the mortar. The mortars can be constructed of any rigid material
such as cardboard, metal or plastic. The pyrotechnic projectile has a
specific orientation within the mortar. The orientation provides for the
outer shell having the initial burst to be arranged so that it is below
the main burst. This type of fireworks display system also produces a loud
noise, from detonation of the initial burst, requiring ear protection at
the launch site. There is no existing method of noise reduction for the
prior art devices. Moreover, existing mortar construction generally is not
conducive to adjustment after installation at the launch site to enable
aiming of the pyrotechnic projectile to different locations in the sky.
Another drawback associated with existing pyrotechnic projectiles and
mortars is their adverse impact on the environment. For example, the
current method of projection using a charge of black powder forms a
residue having a detrimental environmental impact on the ground and any
water area in and around the firing site. The black powder, products of
combustion, and products of incomplete combustion from the pyrotechnic
projectile firing are extremely corrosive agents (e.g., various acids).
These materials, in addition to corroding the existing equipment at the
site, are deposited in the area surrounding the mortar site, both on the
ground and in the water. There are significant adverse effects from this
deposition of sulfuric acid and other harmful chemicals on the soil and
water surrounding the site. Moreover, on the ground, at the time of
firing, there are large quantities of smoke. This smoke can be very
distracting to the guests and may direct their attention away from the
aerial fireworks display. In addition, large quantities of smoke may be
blown by the wind toward the guests, causing further irritation.
Fallout from the pyrotechnic projectile after it has been detonated in the
air creates further environmental concerns. Firework shell casings are
traditionally made from laminated paper or plastic. Paper casings have
been in use since the time of Marco Polo, whereas plastic casings were
introduced approximately 25 years ago. Existing pyrotechnic projectile
shells are not usually completely fragmented and consumed in the air
during detonation of the pyrotechnic projectile into its intended display.
Instead, the shells are incompletely fragmented, and many portions of the
shell, some of them quite large, fall back to the ground. This creates
undesirable litter in an area below the point of the fireworks display.
Portions of the shell falling back to the ground also cause a safety
hazard to people on the ground who could be hit and injured by the
fallout. Moreover, after detonation, portions of the shell can and often
do fall back to the ground as burning debris. This causes a severe fire
hazard in many areas.
In spite of the inability to precisely control fireworks displays, no
change from the existing system has ever been successful because of the
inability to detonate the main burst of the pyrotechnic projectile by
means other than ignition by the initial burst. As previously discussed,
because the black powder provides the propelling charge necessary to
ignite the main fuse of the pyrotechnic projectile, use of any other type
of propulsion means that does not incorporate black powder or its
equivalent does not provide for delayed aerial detonation.
In view of the inaccuracy and drawbacks possessed by existing pyrotechnic
projectiles and mortars, serious limitations are imposed on the
versatility of the resulting pyrotechnic display. For example, the limited
capability to aim the pyrotechnic projectile and control its trajectory
inhibits the ability to send a pyrotechnic projectile to different
locations of the sky having different altitudes. The lack of precision and
timing regarding detonation of the projectile in the air prevents precise
timing of the main burst explosion. Moreover, fireworks shows cannot be
precisely presented in synchronization with programmed material, such as
music and dialogue, nor is it possible to repeatably and consistently
produce a fireworks pattern corresponding to a recognizable shape, in view
of the inaccurate and random nature of firing of the main burst. The
relatively high volume of black powder used in the initial burst, as well
as the main burst, also requires that the projectile be treated with
special care and handling during transportation. In this regard, there are
strict statutory shipping requirements for hazardous materials which
govern the handling and transportation of the pyrotechnic projectiles.
These factors consequently increase fireworks display expense.
Accordingly, there has existed a definite need for a method and system for
launching and detonating projectiles which is more accurate, safe and
versatile, with a minimum adverse environmental impact. The present
invention satisfies these and other needs, and provides further related
advantages.
SUMMARY OF THE INVENTION
The present invention provides a system and method for creating a precision
fireworks pyrotechnic display that is highly accurate and safe, with
greater altitude capability and a substantially decreased environmental
impact. The system comprises a launching device for launching a fireworks
projectile into the air, and an electronic control system including a
controller and an electronic fuse. The electronic fuse is connected to the
projectile and can communicate with the controller such that the
projectile explodes in the air into a fireworks display after a
predetermined time period. The launching device also advantageously uses a
remote, non-explosive launching medium to rapidly expel the projectile
into the air. The system of the present invention furthermore is intended
to be simple in construction, reliable in operation, and low in
maintenance.
More particularly, the new projectile comprises a shell having a main burst
only. This main burst is still designed to explode into the pyrotechnic
display upon ignition by the electronic fuse. However, the shell no longer
is limited in its thickness and structure and can be constructed from
various materials including a composition which is a consumable binding
agent, such as paper or plastic material. The composition of the shell can
also include an additive such that, upon ignition, the shell is exploded
along with the main burst charge into small particles that are rapidly
burned and consumed. As a result, only lightweight, inert particles fall
to the ground, virtually eliminating any safety or fire hazard, and with
minimum environmental impact. Elimination of the black powder ignition at
ground level for the initial burst, as in the prior art system, also
reduces the environmental impact.
In one aspect of the invention, the additive forming the shell composition
is nitrocellulose. Varying shell structures with different nitrocellulose
compositions have been found suitable to completely burn and consume the
shell. A composition having a range of about 0.6 gm/cm.sup.3 to about 1.3
gm/cm.sup.3 nitrocellulose has been used in combination with a plastic
binding agent, but various other ranges and other additives may be used to
accomplish the desired result. In one embodiment, the nitrocellulose is
mixed with the binding agent before forming the projectile shell. In
another embodiment, the binding agent is first formed into the shell, with
the nitrocellulose being applied to an inner surface of the shell. The
shell can take on various shapes, such as cylindrical, spherical and
bullet-shaped. The shell thickness also can be appropriately adjusted
depending on the pressure change to which the projectile will be
subjected.
In another aspect of the invention, the surface of the projectile shell may
be scored to facilitate exploding of the shell into small particles upon
detonation in the air after launch. In one form, the inner surface of the
shell is scored with grooves in the form of intersecting lines. In another
embodiment, the inner surface of the shell contains ridges which also
intersect each other. Thus, when the projectile explodes in the air, it is
completely fragmented into tiny particles which, as noted above, fall
harmlessly to the ground as inert flakes.
The system for creating the fireworks display of the present invention uses
a launching device in the form of a launcher having a non-explosive
launching medium to launch the projectile. In the preferred embodiment,
the non-explosive launching medium is a compressed gas, such as air from a
conventional pressurized air source. By using a non-explosive, remote
launching medium, the need for a black powder initial burst and all of its
associated problems are totally eliminated. It is also possible to
transport the projectile at decreased costs since it is not as explosive
as its prior art counterpart.
In accordance with the invention, the launcher comprises a pressure tank
containing compressed gas and a launching tube having a lower end
connected to the pressure tank and an open end for expelling the
projectile into the air. A valve connected between the pressure tank and
the launching tube is opened and closed in a precise and controlled manner
to accurately introduce an exact, predetermined amount of gaseous medium,
at a controlled pressure, from the pressure tank to the launching tube.
Upon release, the pressure of the gaseous medium rapidly expels the
projectile from the open end of the tube. Typical velocities are in the
500 ft./sec. range. Pressures ranging from 20 psi to 150 are typically
used to launch the projectile to precise altitudes ranging from 50 feet to
2,000 feet in the air or higher. Because the launcher of the present
invention accelerates the projectile by releasing compressed gas behind
the projectile, the maximum pressure is limited, and the pressure rise
never becomes uncontrollable. This allows a higher pressure rise to be
used, resulting in a higher projectile acceleration and higher altitudes,
while staying well below the pressure that could damage the projectile.
In one aspect of the invention, the launcher includes a breech positioned
between the pressure tank and the launching tube for loading the
projectile into the launcher. One embodiment of the breech comprises a
half-cylindrical opening in the lower end of the launching tube through
which the projectile is loaded upwardly into the launching tube. A stop
mechanism, in the form of a pivoting bar connected to the side of the
opening, holds the projectile in a fixed position within the launching
tube at a location above the breech. A sleeve surrounding the launching
tube is adapted to slide axially with respect to the tube between an open
position, in which the sleeve is spaced axially from the opening to permit
loading, and a closed position, in which the sleeve covers the opening to
permit launching. In another embodiment of the breech, instead of a sleeve
the breech includes a door pivotally connected to the breech such that, in
the open position, the door pivots outwardly away from the opening to
permit loading and, in the closed position, the door pivots inwardly to
cover the opening to permit launching. Other embodiments of the breech are
used, such as a multiple breech apparatus.
The launcher also advantageously includes an aiming apparatus for
accurately adjusting the angle of the launching tube with respect to the
ground to thereby change the altitude and trajectory of the launched
projectile. In one embodiment, the aiming apparatus comprises a plurality
of legs which support the launcher. The length of these legs is adjustable
to lower or raise one side of the launcher with respect to the other. This
changes the angle of the launching tube with respect to the ground and
thus the trajectory and altitude of the launched projectile.
The projectile launching system further includes an electronic fuse for
igniting and detonating the explosive charge inside each projectile. The
electronic fuse provides an extremely precise delay time from launch time
to ignition of the projectile. It also decreases the chance of a premature
post-launch ignition or an accidental ignition during ground handling.
Each launcher in the system is controlled by a local control unit which
provides the required electrical energy and data signals to store a
predetermined ignition delay time in the fuse, to initiate a launch and to
provide electrical energy to the fuse. Each local control unit is
controlled by a central controller and can control one or more launchers.
The central controller includes a programmable computer that accepts input
commands from an operator, a display that displays system messages and a
processor that provides appropriate signals to the local control units for
launch communications and control.
The predetermined delay time set by the local control unit is the amount of
time desired to pass from the time of launch to the time the projectile is
ignited and detonated in the air. Prior to launch, the central controller
commands the local control unit to provide the predetermined delay time to
the electronic fuse. The local control unit receives a confirmation signal
after the predetermined delay time has been loaded into the fuse. This
confirmation signal assures that the fuse is functioning properly. After
receipt of the confirmation signal, the local control unit sends a start
command to the fuse and to the launcher. In response, the control unit
opens the valve and admits a predetermined amount of pressure from the
pressure tank to the launch tube for a predetermined time period to launch
the projectile from the tube. After the projectile has been launched, the
fuse confirms that a launch has actually taken place and, if so, waits for
the predetermined delay time before initiating ignition of the main burst
charge inside the projectile shell. If the fuse does not confirm that a
launch has taken place, the fuse is reset. The local control unit can then
signal that an error has taken place or it can re-initiate the launch
sequence.
The electronic fuse and its associated control system provide many
advantages. Chief among them is the ability to provide more precise
projectile detonation times after launch. The fuse used in the present
invention provides a detonation time having an accuracy within 25
milliseconds. When this accuracy is combined with the ability of the
launch tube to launch the projectile to relatively precise altitudes,
detonation of the projectile at a selected location in the sky can be
achieved. By appropriately programming the central controller, a multitude
of projectiles can be launched simultaneously or in series to create a
pattern in the sky upon detonation or to detonate in a manner that is
synchronized with a particular musical score, dialogue or other sounds.
Other features and advantages of the present invention will become apparent
from the following detailed description, taken in conjunction with the
accompanying drawings, which illustrate, by way of example, the principles
of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate the invention. In such drawings:
FIG. 1 is an aerial perspective view of a fireworks display, showing a
display created by existing prior art fireworks technology alongside a
display created by the method and system of the present invention;
FIGS. 2A and 2B show a preferred embodiment of the invention, with FIG. 2A
showing an elevational view of all the described components of the system,
and with FIG. 2B showing an enlarged cross-sectional view of a pyrotechnic
projectile of the system;
FIG. 3 is a cross-sectional elevational view of a launcher for launching a
pyrotechnic projectile of the system;
FIG. 4 is a cross-sectional elevational view of a portion of the launcher,
showing one embodiment of a breech for loading the projectile into the
launcher, with the breech in an open position for loading;
FIG. 5 is another cross-sectional elevational view of the launcher, similar
to FIG. 4, showing a further stage of loading the projectile into the
breech;
FIG. 6 is yet another cross-sectional elevational view of the launcher,
similar to FIG. 4, showing a further stage of loading the projectile into
the breech;
FIG. 7 is still another cross-sectional elevational view of the launcher,
similar to FIG. 4, showing the final stage of loading the projectile into
the breech;
FIG. 8 is a cross-sectional plan view of a portion of the launcher, showing
another embodiment of a breech for loading the projectile into the
launcher, with the breech in an open position for loading;
FIG. 9 is an elevational view of the launcher, taken substantially along
the line 9--9 in FIG. 8;
FIG. 10 is another cross-sectional plan view of the launcher, similar to
FIG. 8, showing the breech in a closed position for launching;
FIG. 11 is an elevational view of the launcher, taken substantially along
the line 11--11 in FIG. 10;
FIG. 12 is a cross-sectional plan view of a portion of the launcher,
showing yet another embodiment of a breech for loading the projectile into
the launcher, with the breech in an open position for loading;
FIG. 13 is an elevational view of the launcher, taken substantially along
the line 13--13 in FIG. 12;
FIG. 14 is another cross-sectional plan view of the launcher, similar to
FIG. 12, showing the breech in a closed position for launching;
FIG. 15 is an elevational view of the launcher, taken substantially along
the line 15--15 in FIG. 14;
FIG. 16 is a cross-sectional elevational view of a portion of the launcher,
showing a further embodiment of a breech for loading a plurality of
projectiles into the launcher;
FIG. 17 is a cross-sectional elevational view of one embodiment of an
assembled projectile in accordance with the present invention;
FIG. 18 is an exploded cross-sectional elevational view of the projectile
of FIG. 17;
FIG. 19 is a cross-sectional elevational view of another embodiment of an
assembled projectile in accordance with the present invention;
FIG. 20 is a cross-sectional elevational view of yet another embodiment of
an assembled projectile in accordance with the present invention;
FIG. 21 is a perspective view of a portion of a projectile, partly in
cross-section, showing scoring in the form of grooves on an inner surface
of the projectile;
FIG. 22 is another perspective view of a portion of a projectile, partly in
cross-section, showing scoring in the form of ridges on an inner surface
of the projectile;
FIG. 23 is a block diagram showing a control system for launching the
projectile from the launcher and detonating it in the air;
FIG. 24 is a block diagram showing in more detail the electronic fuse
system and its connection to the control system;
FIG. 25 is an elevational view representing a pyrotechnic display created
by existing prior art fireworks technology; and
FIG. 26 is an elevational view representing a pyrotechnic display created
by the method and system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in the accompanying drawings, the present invention is embodied in
a system and method for propelling fireworks projectiles to accurate
locations in the air and detonating them in a repeatable and consistent
manner to create an enhanced pyrotechnic display. The system comprises a
fireworks projectile 10 and a launcher 12 for launching the projectile to
precise altitudes, in some cases as much as three or more times higher
than existing systems. The launcher 12 advantageously uses a non-explosive
launching medium to launch the projectile 10 into the air and an
electronic fuse 14 connected to the projectile to explode it in the sky
within a very precise time period after launch. The system further
includes a central control system 15 for controlling one or more launchers
12 and electronic fuses 14. This system and method provides an improved
fireworks show with increased range and accuracy, precision display
choreography, and reduced environmental impact.
FIG. 1 is an aerial perspective view of two fireworks displays 2 and 4. The
display 2 on the lower right portion of FIG. 1 illustrates the type of
limited, imprecise and low altitude fireworks display that is achieved
using existing prior art fireworks technology. There it can be seen that
detonation of the initial burst has caused noticeable quantities of smoke,
indicated by the reference numeral 6, on the ground in the area of the
mortars where it may be distracting to guests observing the display 2. As
each prior art pyrotechnic projectile is propelled in the air, it also
leaves a long trail of smoke 8 that is also quite noticeable. Moreover,
when the prior art pyrotechnic projectile detonates into its intended
display, assuming each pyrotechnic projectile is launched simultaneously
and designed to explode at the same altitude, they will not detonate at
the same time or at the same altitude. This results in a very imprecise,
random and low altitude fireworks display 2.
In contrast, the fireworks display 4 in the upper portion of FIG. 1
illustrates the type of versatile, precise and high altitude fireworks
display that can be achieved using the method and system of the present
invention. With this new and enhanced display 4, there is no undesirable
smoke on the ground nor are there any noticeable trails of smoke to
detract from the display. Moreover, the launching and detonation of the
projectiles 10 can be carefully and precisely controlled by the control
system 15 to detonate the projectiles in such a way that the aerial
explosions create a pattern of a desired shape. In this way, the
pyrotechnic display 4 can be varied and enhanced without limitation to
create a multitude of display patterns. Moreover, the projectile
explosions forming the display 4 can be synchronized to follow music,
dialogue or other sounds.
FIGS. 2A and 2B show a preferred embodiment of the invention and illustrate
the major components of the system. This system comprises the projectile
10, also shown in an associated exploded view in FIG. 2B, and a plurality
of the launchers 12 for launching the projectiles into the air. As noted
above, each launcher 12 advantageously uses a non-explosive launching
medium to rapidly expel the projectile 10 from the launcher where it is
detonated at a precise location in the sky by the electronic fuse 14. As
explained in more detail below, the system and method of the present
invention provide a pyrotechnic display having features and advantages
which have not previously been attainable with existing pyrotechnic
display equipment.
FIG. 3 shows the structure of the launcher 12 in more detail. The launcher
12 comprises a pressure tank 16 and a launching tube 18 containing the
projectile 10 to be launched. The pressure tank 16 contains a compressed
gas, such as air, supplied to the tank from a compressed gas source (not
shown) by a suitable hose 20. The launching tube 18 has a lower end 22
connected to the pressure tank 16 and an open, upper end 24 for expelling
the projectile 10. The launching tube 18 may be cylindrical, as
illustrated in FIG. 3, or it may be another appropriate shape to
accommodate the shape of the projectile 10 being launched. The lower
portion of the pressure tank 16 has a plurality of stabilizers 26 in the
form of triangular-shaped flanges connected to a corresponding number of
support legs 28 which support the launcher 12 on a relatively horizontal
ground surface 30 or other platform. To adequately support the launcher
12, there should be at least three stabilizers 26 and support legs 28.
However, additional stabilizers 26 and support legs 28 may be provided as
may be necessary or desired.
The introduction of pressure from the pressure tank 16 to the launching
tube 18 is controlled by a valve 32 connected between the launching tube
18 and the pressure tank 16. When it is desired to launch the projectile
10 and the pressure tank 16 is at the appropriate pressure level, the
valve 32 is opened for a predetermined period of time to allow an exact
volume of compressed gas to enter the lower end 22 of the launching tube
18 underneath the projectile 10. The force of the compressed gas rapidly
accelerates and expels the projectile 10 from the open end 24 of the
launching tube 18. By accurately controlling the pressure in the tank 16
and the amount of pressure admitted into the launching tube 18 by the
valve 32, the projectile 10 can be launched into the air to a relatively
precise altitude and at a relatively precise velocity. In the preferred
embodiment of the invention, the pressure tank 16 is pressurized to levels
from 20 psi to 150 psi to enable launching of the projectile 10 to
altitudes ranging from 50 feet to 2,000 feet or higher, with tube exit
velocities as high as 500 ft./sec.
The valve 32 which opens and closes to admit pressure from the pressure
tank 16 into the launching tube 18 can be of any suitable construction, so
long as it is fast acting, with a minimum opening time on the order of 12
milliseconds. It also must be capable of withstanding the pressures
involved. In one embodiment of the invention, a butterfly valve has been
used. Suitable butterfly valves are available from Fisher Controls, such
as an 8 inch valve identified as Type 1066, Body 8522. The pressure tank
16 preferably is constructed from metal, and the launching tube 18 may be
constructed from suitable rigid materials, such as metal, plastic or
fiberglass. When fiberglass materials and the like are used, it may be
desirable to add an internal coating designed to reduce the charge created
in the launching tube 18 during launching of the projectile 10.
The stabilizers 26 and support legs 28 described above are adjustable with
respect to each other to enable aiming of the launching tube 18. More
particularly, the stabilizers 26 are connected to the support legs 28 by a
connector 34, which may be a threaded nut on the support legs 28. By
moving one or more of the connectors 34 axially with respect to the
support legs 28, one side of the launcher 12 may be raised or lowered with
respect to the other. This adjustment changes the angle of the launching
tube 18 with respect to the ground 30. As a result, the trajectory of the
launched projectile 10 may be controlled to aim the projectile to a
particular location in the sky for detonation.
Since the launching medium used to launch the projectile 10 is
non-explosive, there is no black powder charge as in the prior devices. As
a result, there is no objectionable cloud of smoke causing a visual
intrusion on the ground which might detract from the fireworks display.
There also is no burning debris which may inadvertently ignite adjacent
projectiles or other combustible materials in the surrounding area.
Furthermore, the lack of a ground launching explosion eliminates the
generation of corrosive agents or other harmful chemicals, which could
corrode the launch equipment and surrounding area or otherwise cause a
detrimental environmental impact in the launch area. Maintenance of the
launch equipment also is kept to a minimum.
FIGS. 4-7 show one embodiment of a breech 36 for loading the projectile 10
into the launching tube 18. The breech 36 comprises an opening 38 in the
lower end 22 of the launching tube 18 through which the projectile is
loaded. Since the launching tube 18 in the preferred embodiment is
cylindrical, the opening 38 is shown as being a half-cylindrical opening
having an axial length that is slightly greater than the length of the
projectile 10. The breech 36 also comprises a cover in the form of a
cylindrical sleeve 40 which surrounds the launching tube 18. The sleeve 40
is adapted to be moved axially with respect to the launching tube 18
between an open position and a closed position. In the open position,
shown in FIGS. 4-6, the sleeve 40 is axially spaced from the opening 38 to
permit loading of the projectile 10 into the launching tube 18. In the
closed position, shown in FIG. 7, the sleeve 40 covers the opening 38 to
permit launching of the projectile 10.
In use, the sleeve 40 is moved to the open position and a bar 42, pivotally
connected to one side of the opening 38, is pivoted outwardly away from
the opening, as shown in FIG. 4. The projectile 10 is then inserted
through the opening 38 and upwardly into the launching tube 18 at a
location above the bar 42, as shown in FIG. 5. The bar 42, which is
attached toward the upper end of the opening 38, is then pivoted inwardly
toward the other side of the opening 38 such that the bar 42 is
substantially aligned along a diameter of the launching tube 18. In this
position, the bar 42 provides a stop mechanism for maintaining the
projectile 10 at a fixed position within the launching tube 18, as shown
in FIG. 6. To conclude the projectile loading operation, the sleeve 40 is
moved axially downward to completely cover the opening 38, as shown in
FIG. 7.
FIGS. 8-11 show another embodiment of the breech 36 for loading the
projectile 10 into the launching tube 18. In this embodiment, the breech
36 includes the same half-cylindrical opening 38 in the lower portion of
the launching tube 18, similar to the embodiment of the breech 36
discussed above in connection with FIGS. 4-7. However, instead of using a
sliding sleeve 40 to cover the opening 38, the breech 36 includes a door
44 pivotally connected to one side of the opening 38. In the open
position, shown in FIGS. 8-9, the door 44 is pivoted outwardly away from
the opening 38 to permit loading of the projectile 10. In the closed
position, shown in FIGS. 10-11, the door 44 is pivoted inwardly to cover
the opening 38 to permit launching. The door 44, which is preferably
half-cylindrical in shape, has one side pivotally connected to the
launching tube 18 by suitable hinges 46 on one side of the opening 38. The
other side of the door 44 is connected to the other side of the opening 38
by a suitable latching mechanism 48. The latching mechanism 48 illustrated
includes a tongue 50 on the door 44 adapted to engage a groove 52 on the
latching mechanism 48 to securely close the door 44 over the opening 38.
It will be appreciated, however, that other appropriate latching
mechanisms may be employed to secure the door 44 over the opening 38.
FIGS. 12-15 show yet another embodiment of the breech 36 for loading the
projectile 10 into the launching tube 18. In this embodiment, the breech
36 comprises a cylindrical enclosure 54 having an upper flange 56 for
pivotally connecting the launching tube 18 to the enclosure 54 and a lower
flange 58 for connecting the enclosure to the pressure tank 16. The
enclosure 54 includes a cylindrical tube 60 into which the projectile 10
is loaded. In the open position, shown in FIGS. 12-13, the launching tube
18 is pivoted outwardly away from the enclosure 54 to permit loading of
the projectile 10. In the closed position, shown in FIGS. 14-15, the
launching tube 18 is pivoted inwardly to align with the enclosure 54 to
permit launching. Thus, by appropriately pivoting the launching tube 18,
the launching tube 18 may be moved into and out of registration with the
enclosure's cylindrical tube 60.
FIG. 16 shows yet another embodiment of the breech 36 for loading a
plurality of projectiles 10, one at a time, into the launching tube 18. In
this embodiment, the breech 36 includes a row of cylindrical tubes 62
containing the projectiles 10 to be launched. Each of the tubes 62 is
moved successively into registration with the launching tube 18 after the
projectile in the previous tube has been launched. In one embodiment of
the breech, the cylindrical tubes 62 are arranged in a straight row, while
in another embodiment the cylindrical tubes 62 may be arranged in a
circular or cylindrical manner. Appropriate means (not shown) may be
provided for indexing the cylindrical tubes 62 such that the projectiles
10 may be launched in succession at a predetermined time or rate.
The projectile 10 used in the present invention is unique in both its
structure and explosive properties. For example, the bullet-shaped
projectile shown in FIGS. 17-18 comprises a projectile shell 64, including
an upper shell 66 and a lower shell 68. The lower shell 68 contains an
explosive burst charge 70 and a composition 72, such as stars or
flash-and-sound powder, adapted to explode into the pyrotechnic display
upon ignition and detonation of the explosive charge 70. The lower shell
68 also houses the electronic fuse 14, which ignites a squib 74 upon
ignition sending a flame upwardly through a cylindrical sleeve 76 to
detonate the burst charge 70. The sleeve 76 also holds and positions the
burst charge 70 in place, surrounded by the composition of stars 72. In
accordance with the invention, the shell 64 which contains the explosive
burst charge 70 is constructed from a special composition comprising a
consumable binding agent and an additive, such as an explosive additive.
This structural composition of the projectile 10 advantageously provides a
shell 64 that is exploded along with the burst charge 70 into small
particles that are rapidly burned and consumed such that they fall
harmlessly to the ground as lightweight, inert flakes.
In one preferred embodiment of the projectile 10, the binding agent is a
paper or plastic material and the additive is nitrocellulose. Although the
amount of nitrocellulose or other additive in the shell 64 may vary, a
shell containing a range of between about 0.6 gm/cm.sup.3 to about 1.3
gm/cm.sup.3 nitrocellulose has been found to be suitable to cause rapid
burning and consumption of the small particles of the shell following the
explosion in the air. In one forth of the invention, the nitrocellulose is
mixed with the fibers of the binding agent to form the shell 64. In
another embodiment, the binding agent is initially formed into the shell
64 and the nitrocellulose is subsequently applied to an inner surface of
the shell. The shell 64 may be formed by molding or other suitable
techniques. It will be appreciated that other types of explosive or highly
flammable additives may be used in appropriate amounts to ensure that,
upon detonation, the exploded projectile shell particles will be rapidly
burned and consumed before reaching the ground.
Projectiles 10 manufactured in accordance with the present invention
preferably include a plastic binding agent, such as white fiber reinforced
plastic, in combination with a nitrocellulose composition. This
composition includes approximately 40-70 percent nitrocellulose, 15-40
percent cellulose, 7-13 percent cured polyurethane resin and 0.5 to 1.5
percent N'-methyl-N,N-diphenylures. Nitrocellulose compositions of this
nature are available from Olin Corporation of Stamford, Conn. under
Product Code DPE04000.
FIGS. 19-20 show other shapes of the projectile. For example, FIG. 19 shows
a cylindrically shaped projectile 10, while FIG. 20 shows a spherically
shaped projectile 10. Each of these projectiles 10 have the same
components of the bullet-shaped projectile 10 shown in FIGS. 17-18, such
as the explosive burst charge 70, a composition 72 such as stars, and a
fuse 14. However, each of these differently-shaped projectiles 10 produces
a different form of pyrotechnic display when exploded in the air.
Accordingly, by appropriately selecting the projectile 10 having the
desired pyrotechnic display properties, a variety of pyrotechnic displays
can be achieved.
To facilitate exploding of the shell 64 into small particles when the
explosive burst charge 70 inside the shell is detonated in the air, the
inner surface 78 of the shell 64 is scored, as shown generally by the
reference numeral 80 in FIG. 18. More particularly, in one preferred form,
shown in FIG. 21, the inner surface 78 of the shell 64 is scored with a
plurality of horizontal grooves 82 which intersect a plurality of vertical
grooves 84. These grooves 82 and 84 extend into the projectile shell 64 a
distance equal to approximately one-half the thickness of the shell. In
another preferred form, shown in FIG. 22, the inner surface 78 of the
shell 64 is scored with a plurality of horizontal ridges 86 which
intersect a plurality of vertical ridges 88. These ridges 86 and 88 extend
radially inward from the inner surface 78 of the shell 64 by a distance
equal to approximately one-half the thickness of the shell. Appropriate
molds can be formed to construct the shell 64 and form suitable grooves 82
and 84 or ridges 86 and 88 on the inner surface 78 of the shell to
facilitate exploding of the shell into small particles when the explosive
burst charge 70 inside the shell 64 is detonated in the air. For example,
for a nominal six inch shell, the horizontal and vertical grooves and/or
ridges can be spaced apart by about 3/8 inch to 1 inch. Of course, it will
be appreciated that other geometric patterns of grooves 82 and 84 and
ridges 86 and 88 may be provided on the inner surface 78 of the shell 64
to accomplish the purpose of exploding the shell into very small particles
upon detonation of the explosive burst charge.
Fallout from the projectile 10 after it has been detonated in the air has a
substantially decreased environmental impact. Unlike prior projectile
shells, which are not completely fragmented and consumed in the air upon
detonation, the projectile shell 64 of the present invention is completely
fragmented into extremely small particles which are rapidly burned and
consumed before reaching the ground. Hence, there are no large or burning
portions of the shell 64 falling to the ground which could cause a safety
or fire hazard. Instead, only lightweight, inert particles fall lightly to
the ground as harmless flakes producing the least possible environmental
impact. In addition, the use of compressed gas to launch the projectile 10
allows the shell 64 to be somewhat thicker than before. This allows the
projectile 10 to be launched to a higher altitude than its prior art
counterpart, since the thicker shell can withstand higher launching
pressures.
FIGS. 23-24 show block diagrams of the pyrotechnic control system 15 and
the electronic fuse 14 for igniting and detonating the explosive charge 70
inside each projectile 10. The electronic fuse 14 provides an extremely
precise delay time from the time of launch to ignition of the projectile
10. In the preferred embodiment, the fuse has an accuracy within 25
milliseconds. The fuse also decreases the chance of a premature
post-launch ignition or an accidental ignition during ground handling of
the projectile 10.
Each launcher 12 in the control system 15 is controlled by a local control
unit 90 which provides the required electrical energy and data signals to
store a predetermined ignition delay time in the fuse 14, to initiate a
launch and to provide electrical energy to the fuse 14 for ignition of the
projectile 10. Each local control unit 90, which can control one or more
launchers 12, is in turn controlled by a central controller 92.
The block diagram of FIG. 23 illustrates how show control electronics 94
provide timing signals via a signal line 96 to the central controller 92.
As noted above, the central controller 92 communicates with the local
control unit 90 that is associated with each launcher 12 of the
pyrotechnic control system 15. In FIG. 23, the central controller 92 is
shown connected to the local control unit 90 by a communication line 98.
The local control unit 90 sends control data and receives sensor data from
the launcher 12. The electronic fuse 14 associated with each projectile
communicates with the local control unit 90 via a launch cord 100. The
central controller 92 generates a control signal that causes the local
control unit 90 to program the correct delay time into the electronic fuse
14. The local control unit 90 thereafter opens the valve 32, causing the
projectile 10 to be launched. The projectile is then detonated at a
predetermined time after launch and, therefore, at a predetermined
location in the sky.
In one embodiment, the central controller 92 includes a serial
communications interface 102 for communication with each local control
unit 90, a timing signal interface 104 for receiving timing signals from
the show control electronics 94, a keyboard and manual controls 106 and
also a display 108 for interface with operators, and a processor 110 for
controlling the interaction of these elements. The timing signal interface
104 is a combination of hardware and software that provides a signal to
the processor 110 of the central controller 92 to automatically generate
commands that are used to launch and fire the projectiles 10.
Alternatively, the timing signal interface 104 can be configured to accept
an external timing signal, such as time codes of the Musical Instrument
Digital Interface (MIDI) design standard or of the Society of Motion
Picture and Television Engineers (SMPTE), or to accept tone bursts or
other digital signals. In this way, the pyrotechnic show control
electronics 94 can be synchronized with these signals to time the
detonation of the projectiles 10 in the air to correspond with the beat of
music, dialogue or other sounds or visual displays.
The central controller 92 provides each local control unit 90 with control
and status data over the communications line 98. The local control unit 90
is coupled to the communications line 98 via a serial interface 112. The
serial interface 112 accepts data from the central controller 92 and
formats the data into a form that is useable by a microcontroller 114 of
the local control unit 90. The local control unit 90 operates under
control of the microcontroller 114, which in turn communicates with the
launcher 12 via a launcher interface 116 and communicates with the fuse 14
via a fuse or igniter interface 118.
The serial interface 112 includes data line protection components, a data
line transceiver, addressing switches, and associated firmware for data
encoding and error checking. The launcher interface 116 includes
electronic and electromechanical components that are needed to receive and
send control data from the launcher 12. The microcontroller 114 can be a
programmable processor that sequences the launcher interface 116 and
igniter interface 118 as well as senses the status of the interfaces
through digital and analog input and output signals. The microcontroller
114 includes firmware and can also include data stored in ROM or EPROM.
The electronic fuse 14, shown in more detail in FIG. 24, communicates with
the local control unit 90 via the igniter interface 118 and includes a
counter 120 for producing a sequence of clock pulses and a delay time
storage 122 for storing a count of the clock pulses. The electronic fuse
14 includes electrical storage components 124, such as capacitors, for
storing electrical energy that is later released in a manner sufficient to
ignite the projectile 10 after a sufficient number of clock pulses have
been counted to constitute the desired delay time.
Prior to launch, the predetermined delay time is received by the electronic
fuse 14 from the local control unit 90. A delay time confirmation signal
is sent from the fuse 14 to the local control unit 90 and confirms proper
functioning of the fuse. If the local control unit 90 does not receive the
delay time confirmation signal, the local control unit can re-set the fuse
14 or the launch sequence can be halted. If the delay time confirmation
signal is correctly received, indicating that the predetermined delay time
has been correctly loaded, the local control unit 90 will send the fuse 14
and the launcher 12 a command signal to begin the launch sequence.
After the launcher 12 has pressurized the launching tube 18, the projectile
10 will start to rapidly move up the launching tube 18. Shortly after this
movement begins, the launch cord 100 will be severed and the projectile 10
will clear the launching tube 18. The fuse 14 will detect this severing of
the cord 100 as the absence of voltage at the fuse input terminal. The
presence of a voltage at the fuse input terminal indicates that launch has
not taken place. This will cause the fuse 14 to send a signal to the local
control unit 90, which will reset the fuse. If a normal launch has
occurred, the counter 120 in the fuse 14 will allow the predetermined time
delay to pass and then will discharge the storage capacitors, igniting the
projectile 10 and triggering the explosive burst charge 70.
In another embodiment of the invention, the control system 15 and its fuse
14 further include a counter 120 having a two-step sequence, comprising a
pre-counter sequence and a launch sequence. This two-step sequence for
fuse function is embodied in hardwired logic in the fuse 14. The two-step
sequence may be preferred over the single step launch sequence described
above, as it provides for additional safety and prevents interference from
charge which may be found in the launching tube 18 during the launching
operation.
The method of creating the pyrotechnic display and operation of the system
will now be summarized in conjunction, for example, with the two-step
sequence. Prior to the pyrotechnic display or show, the valve 32 in the
launcher 12 is closed and the pressure tank 16 is pressurized to a low
pressure. The control system 15 monitors this pressure to check for leaks.
After disconnecting all power from the local control unit 90, an operator
loads the projectile 10 into the breech 36 and secures it within the
launching tube 18 after connecting the launch cord 100 between the
projectile 10 and the local control unit 90. Closer to show time, the
operator pressurizes the pressure tank 16 to the maximum system pressure
and makes appropriate checks to ensure there is no error. The operator
then vents the pressure tank 16 until it reaches a desired pressure level
to launch the projectile 10 to a selected altitude. This pressure level is
constantly monitored and adjusted until launch.
Prior to the launch, a DC voltage is applied across two input wires leading
to the fuse 14. This current is monitored by the controller 92, and if no
current is seen, the polarity is reversed. This allows the operator to
connect the fuse leads 100 without checking polarity so that the
connection is essentially foolproof. After hookup, an exponentially
decreasing current should be seen, characteristic of a charging capacitor,
which tells the operator to proceed to the next step. The controller 92
next sends a digital pulse train to the fuse 14 containing the value to
load into the counter 120. After receiving this information, the fuse 14
sends a pulse train back to the controller 92 which uses this information
to verify that the fuse 14 is operational and that it was programmed with
the correct count.
After the fuse 14 has been charged, programmed and verified, a command by
digital pulse train is sent from the controller 92 to the fuse 14 to start
the pre-counter sequence. The pre-counter sequence is a safety device
having two distinct purposes. First, it prevents dangerously short times
from being programmed into the counter 120. Even if a time of zero has
been programmed, the fuse 14 will not fire until the pre-counter time has
elapsed. Second, it shields the fuse 14 from electrical noise during
launch. When the command is given to start the pre-counter sequence, the
inputs to the fuse 14 are disabled, so any noise picked up by the fuse
leads 100 during launch, therefore, will be isolated from the fuse 14.
At the time the pre-counter sequence is started, the local control unit 90
opens the valve 32 and launches the projectile 10. The operator then
checks the tank pressure to confirm that pressure was actually vented and
launch has occurred. If not, the error is corrected. When the pre-counter
sequence has elapsed, the fuse 14 re-enables its inputs. If the fuse 14
detects that it is still connected to the local control unit 90, then it
knows that the projectile 10 has not been launched successfully and it
immediately discharges its capacitor to a suitable ground and enters a
safe state. However, if it sees that its leads 100 have been disconnected,
the launch sequence counter 120 is started and, when the main count
elapses, the squib 74 is fired by the fuse 14 sending a flame up the
sleeve 76 to detonate the burst charge 70 of the projectile 10.
FIG. 25 shows, in general, another type of limited pyrotechnic display 126
which the prior art systems are presently capable of achieving. In this
example, the projectiles are designed to explode into the intended display
at an altitude of approximately 600 feet. However, because the prior art
pyrotechnic display systems are inherently prone to inaccuracy, for the
reasons previously described, the projectiles will detonate at an altitude
anywhere between 500-700 feet. This is a deviation of more than 16
percent. Moreover, even when these projectiles are all launched at about
the same time, they generally will not explode simultaneously, primarily
due to the lack of uniformity in chemical fuse construction.
In contrast, FIG. 26 illustrates another pyrotechnic display 128 of the
type which may be achieved by the method and system of the present
invention. Here, projectiles 10 designed to explode at an altitude of 600
feet will explode at an altitude between approximately 560-640 feet. This
variation of 40 feet on either side represents a deviation of only about
6.7 percent. As noted above, prior art pyrotechnic displays have a
deviation in the range of 16 percent or more.
The pyrotechnic display 128 of FIG. 26 also illustrates a plurality of
detonated projectiles 130 synchronized by the control system 15 to
detonate substantially at the same time to form a particular shape or
pattern in the sky. Alternatively, as noted above, detonation of the
projectiles 10 can be synchronized to music, dialogue or other sounds by
the control system 15, in view of the precise timing of the projectile
detonation. Also, since the projectiles 10 can be launched to high
altitudes at various locations in the sky, due to the launcher's precise
aiming capabilities and relatively high launch velocities, an endless
pattern of pyrotechnic displays 130 can be created at a variety of
locations above the ground 30.
In addition to the precision provided by the method and system of the
present invention, the projectiles 10 are capable of being launched as
much as three times higher, and perhaps more, than the existing prior art
projectiles. For example, a nominal 6 inch prior art projectile can be
launched only to about 600 feet, while a 6 inch projectile 10 of the
present invention can be launched to altitudes of 2,000 feet and higher.
As a general rule, the existing prior art projectiles, at the largest
practical size, have a ceiling of about 1,000 feet, whereas the ceiling
for the projectiles 10 of the present invention is more than three times
higher.
From the foregoing, it will be appreciated that the system and method of
the present invention provide an accurate, safe and reliable air-launched
fireworks display system. The system advantageously eliminates initial
burst propelling charges and undesirable fallout of the prior art, thereby
providing a safe and environmentally compatible system. The accuracy of
the electronic fuse 14, in combination with the accuracy and versatility
of the launcher 12, as controlled by the control system 15, in conjunction
with the precision aerodynamic shape of the projectile 10, provides a
precision pyrotechnic display which can be programmed to produce distinct
patterns in the sky or synchronized to follow music, dialogue or other
sounds.
While a particular form of the invention has been illustrated and
described, it will be apparent that various modifications can be made
without departing from the spirit and scope of the invention. Therefore,
it is not intended that the invention be limited, except as by the
appended claims.
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